Ngata missed the past four games for violating the NFL's policy on performance-enhancing drugs. He has been practicing with the team all week.

Before the suspension, Ngata was having one of his best seasons in recent memory. He had two sacks, two interceptions, two forced fumbles and seven batted passes.

In 20 meetings with the Steelers (including two playoff games), Ngata has recorded 76 tackles, 7.5 sacks, two interceptions, one forced fumble and four batted passes.

"This guy has made as many splash plays in the recent history of this series as anybody, whether it’s blowing up the running game, making plays in the backfield or being aware and catching the ball," Steelers coach Mike Tomlin said. "He is just that type of dynamic, big-body guy. He is a big-body guy that can play in all situations and circumstances. He plays more snaps than most people that look like him. He has a big-time impact on the game."

To make room for Ngata on the roster, the Ravens placed linebacker Arthur Brown on injured reserve. Brown injured his hamstring in the regular-season finale, and the former second-round pick hasn't practiced all week.

He becomes the 19th Raven to be placed on injured reserve, tying the most they team has had in coach John Harbaugh's seven seasons. The Ravens also had 19 players on IR in Harbaugh's first season (2008).